Field of the Invention
The present invention relates to a brake apparatus of a vehicle and a method thereof. More particularly, the present invention relates to a brake apparatus of a vehicle and a method that can reduce braking distance by minimizing a pitch motion generated when the vehicle quickly brakes.
Description of Related Art
Generally, in a hydraulic pressure brake system, a hydraulic brake pressure generated by operation of a brake pedal is supplied to each wheel, thereby a vehicle is braked. At this time, a slip between the tire and a road occurs when a braking force that is larger than a static friction force is supplied to a tire.
As is known, a dynamic friction coefficient is less than a static friction coefficient. In order to exhibit optimal brake effect, slipping between the tire and the road must be prevented. In addition, locking up of the brake during slipping must be prevented.
Thus, an antilock brake system (ABS) is used for preventing slip and locking up by controlling hydraulic brake pressure supplied to each wheel. The ABS includes a plurality of solenoid valves controlling the hydraulic brake pressure transmitted to each hydraulic pressure brake, an accumulator, an electric control unit (ECU) controlling a hydraulic pressure control apparatus, and electric/electronic devices such as a hydraulic pressure pump.
The ABS detects a slip generated by operation of a brake on a slippery road or during quick braking, and reduces, sustains, or increases the hydraulic brake pressure such that the vehicle can obtain optimal cornering force and stop at a shortest distance while maintaining steering stability.
Meanwhile, as shown in FIG. 1, since a mass center of a vehicle body is positioned at a higher position compared to a suspension, a pitch motion (in other words, a ‘nosedive’) in which a front portion of the vehicle body falls toward the ground is generated when a driver strongly presses a brake pedal for quick braking.
At this time, when the ABS is operated, a high hydraulic brake pressure is formed at driving wheels by a hydraulic pressure control apparatus, and braking distance becomes longer as the hydraulic brake pressure supplied to the driving wheels is reduced, thereby deceleration is reduced. Therefore, there is a problem that a braking distance becomes longer.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.